How use Substitute for Escape Sequences in Double Quotes?

How to substitute a literal "escape sequence" within a double quoted string? Problem I'm having is that JMP always wants to evaluate the "escape sequence" and not give me its literal character representation:

Source string:

myStr = "C:\temp\myfile.csv";

What I want:

myStr = "C:\!\temp\!\myfile.csv";

The following methods don't work or at least don't appear so when I check them in the Log window (wonder, is that my problem maybe, that the Log window always evaluates?):

myStr = Substitute(myStr,"\","\!\"); ==>doesn't work as it evaluates "\!\" and turns it back into a "\"

myStr = Substitute(myStr,"\","\" || "!" || "\"); ==>doesn't work as it evaluates this again and gives me double "\!\" essentially